The BBC Trust is to appoint an independent adviser to examine director general Mark Thompson's proposals for cutting costs by 20%, once the list of changes and options are presented to the body in June.

It is also planning to lead consultations with BBC stakeholders, including licence fee payers, on the "Delivering Quality First" proposals, before it finally agrees to a reshaped corporation by the end of 2011, according to a newly published trust work plan for 2011/12.

This signals the BBC Trust's intention, under new chairman Lord Patten, who starts in May, to act as the independent regulator and guardian of the public interest, in what will be an unprecedented period of cutbacks at the BBC.

It also signals a refusal to be browbeaten by the executive board, chaired by Thompson, which includes powerful external directors, such as Barclays chairman Marcus Agius, who is head of the remuneration committee.

In its work plan the trust says "we will monitor and ensure, regardless of financial pressures, that the BBC is becoming more distinctive, more efficient, more transparent".

The trust has said it sees savings falling into two categories, firstly those that do not affect output but cut the cost base through back office savings and changed working practices. Then there is the second, cuts that affect output.

"We recognise ... there will still have to be further reshaping of the BBC's services and boundaries," the trust added.

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